The UK air traffic control outage in September 2026 that disrupted hundreds of thousands of travellers was caused by a software defect in NATS’ flight data system. NATS CEO Martin Rolfe detailed the defect originated from a specific subsection of code where a higher-priority request interrupted an aircraft identification code request, triggering a system pause. This error activated backup protocols requiring manual flight handovers and reduced capacity, resulting in prolonged delays.
Flight Cancellations and Passenger Impact at UK Airports
The technical issue led to around 2,000 flight cancellations across UK airports last week, with Heathrow and Gatwick airports experiencing over 250 cancellations on a single recent day. British
Airways cancelled or diverted more than 100 flights, affecting tens of thousands of customers. Ryanair cancelled over 50 flights and disrupted more than 65,000 passengers, mainly in London hubs and other key airports including Liverpool, Birmingham, and Edinburgh.
Delays forced passengers to endure extended waits on the tarmac; at Gatwick one passenger reportedly disembarked following a three-hour delay on the runway. The disruption impacted scheduled routes such as flights from Dublin to the UK and those involving the Arsenal football team’s travel, which had to cancel a news conference due to delays.
Official Responses and Calls for Leadership Change
UK Transport Minister Heidi Alexander condemned the disruption
as “completely unacceptable” and demanded an independent review by the Civil Aviation Authority. She emphasized urgent investigation into why the defect was not detected prior to causing widespread chaos, stating, “It is crucial that our national infrastructure is fit for the future.”
Ryanair’s Chief Operations Officer Neil McMahon criticised NATS CEO Martin Rolfe and reiterated calls for his resignation. McMahon stated, “Martin Rolfe has run out of excuses. The ‘software ate my homework’ is not an acceptable explanation,” and questioned how many failures must occur before action is taken.
Martin Rolfe acknowledged the problem, explaining, “The issue has been identified
and mitigation is in place while a permanent fix is safety tested and deployed.” He added safety was not compromised during the incident and described the network recovery as “very complex,” warning a full return to normal capacity will take time.
Background on UK Air Traffic Control Disruptions
This September 2026 failure is distinct from a 2023 outage, which was triggered by a “one in 15 million” event involving duplicated waypoint names in a flight plan and cost airlines approximately £100 million. Another NATS fault in July 2025 resulted in 150 cancellations due to radar issues. NATS has faced repeated scrutiny following multiple high-impact disruptions over recent
years.
According to the NATS report, the September 2026 incident could have been avoided by microseconds, as the precise timing of conflicting system requests triggered the failure and fallback to manual procedures, severely limiting air traffic throughput.
Travel Disruptions at Heathrow and Gatwick
Heathrow and Gatwick airports faced heavy cancellations exceeding 250 flights in one day, compounding delays across the UK network. British Airways bore a significant share of the impact with over 100 flights cancelled or diverted. Ryanair also faced serious disruption, with flight cancellations and more than 65,000 passengers affected.
Passengers endured delays on runways, longer wait times, and disrupted journeys, particularly on London
routes and key domestic links. Airlines and airports continue to manage recovery efforts amid ongoing system constraints.
